Example lifetime problem

walker.rs

struct RepositoryHolder {
    repository: std::rc::Rc<git2::Repository>,
}

impl RepositoryHolder {
    fn commits(&self) -> impl Iterator<Item = git2::Commit> {
        let repo = self.repository.clone();
        self.walker()
            .flat_map(move |oid| repo.find_commit(oid.expect("Revwalk didn't get oid")))
        // maybe I want to filter the commits by whether they touched a path:
        /*
        .filter(|commit| {
            let parent_tree = commit.parent(0).ok().map(|p| p.tree().ok()).flatten();
            let diff = self
                .repository
                .diff_tree_to_tree(parent_tree.as_ref(), commit.tree().ok().as_ref(), None)
                .expect("Unable to create diff");
            diff.deltas().any(|delta| {
                delta.old_file().path().map(|p| p.to_str()).flatten() == Some("src/main.rs")
                    || delta.new_file().path().map(|p| p.to_str()).flatten()
                        == Some("src/main.rs")
            })
        })
        */
    }

    fn walker(&self) -> git2::Revwalk {
        let mut walker = self
            .repository
            .revwalk()
            .expect("Unable to initialie revwalk");
        // could do other things here, like pushing a revision specifier instead
        walker.push_head().expect("Unable to push head");
        walker
    }
}